Development of Small-Molecule Fluorescent Probes Targeting Enzymes.

As biological catalysts, enzymes are vital in controlling numerous metabolic reactions. The regulation of enzymes in living cells and the amount present are indicators of the metabolic status of cell, whether in normal condition or disease. The small-molecule fluorescent probes are of interest because of their high sensitivity and selectivity, as well as their potential for automated detection. Fluorescent probes have been useful in targeting particular enzymes of interest such as proteases and caspases. However, it is difficult to develop an ideal fluorescent probe for versatile purposes. In the future, the design and synthesis of enzyme-targeting fluorescent probes will focus more on improving the selectivity, sensitivity, penetration ability and to couple the fluorescent probes with other available imaging molecules/technologies.

P300/CBP inhibition sensitizes mantle cell lymphoma to PI3Kδ inhibitor idelalisib.

Mantle cell lymphoma (MCL) is a lymphoproliferative disorder lacking reliable therapies. PI3K pathway contributes to the pathogenesis of MCL, serving as a potential target. However, idelalisib, an FDA-approved drug targeting PI3Kδ, has shown intrinsic resistance in MCL treatment. Here we report that a p300/CBP inhibitor, A-485, could overcome resistance to idelalisib in MCL cells in vitro and in vivo. A-485 was discovered in a combinational drug screening from an epigenetic compound library containing 45 small molecule modulators. We found that A-485, the highly selective catalytic inhibitor of p300 and CBP, was the most potent compound that enhanced the sensitivity of MCL cell line Z-138 to idelalisib. Combination of A-485 and idelalisib remarkably decreased the viability of three MCL cell lines tested. Co-treatment with A-485 and idelalisib in Maver-1 and Z-138 MCL cell xenograft mice for 3 weeks dramatically suppressed the tumor growth by reversing the unsustained inhibition in PI3K downstream signaling. We further demonstrated that p300/CBP inhibition decreased histone acetylation at RTKs gene promoters and reduced transcriptional upregulation of RTKs, thereby inhibiting the downstream persistent activation of MAPK/ERK signaling, which also contributed to the pathogenesis of MCL. Therefore, additional inhibition of p300/CBP blocked MAPK/ERK signaling, which rendered maintaining activation to PI3K-mTOR downstream signals p-S6 and p-4E-BP1, thus leading to suppression of cell growth and tumor progression and eliminating the intrinsic resistance to idelalisib ultimately. Our results provide a promising combination therapy for MCL and highlight the potential use of epigenetic inhibitors targeting p300/CBP to reverse drug resistance in tumor.

Targeting p300/CBP Attenuates Hepatocellular Carcinoma Progression through Epigenetic Regulation of Metabolism.

Targeting epigenetics in cancer has emerged as a promising anticancer strategy. p300/CBP is a central regulator of epigenetics and plays an important role in hepatocellular carcinoma (HCC) progression. Tumor-associated metabolic alterations contribute to the establishment and maintenance of the tumorigenic state. In this study, we used a novel p300 inhibitor, B029-2, to investigate the effect of targeting p300/CBP in HCC and tumor metabolism. p300/CBP-mediated acetylation of H3K18 and H3K27 increased in HCC tissues compared with surrounding noncancerous tissues. Conversely, treatment with B029-2 specifically decreased H3K18Ac and H3K27Ac and displayed significant antitumor effects in HCC cells in vitro and in vivo. Importantly, ATAC-seq and RNA-seq integrated analysis revealed that B029-2 disturbed metabolic reprogramming in HCC cells. Moreover, B029-2 decreased glycolytic function and nucleotide synthesis in Huh7 cells by reducing H3K18Ac and H3K27Ac levels at the promoter regions of amino acid metabolism and nucleotide synthesis enzyme genes, including PSPH, PSAT1, ALDH18A1, TALDO1, ATIC, and DTYMK. Overexpression of PSPH and DTYMK partially reversed the inhibitory effect of B029-2 on HCC cells. These findings suggested that p300/CBP epigenetically regulates the expression of glycolysis-related metabolic enzymes through modulation of histone acetylation in HCC and highlights the value of targeting the histone acetyltransferase activity of p300/CBP for HCC therapy. SIGNIFICANCE: This study demonstrates p300/CBP as a critical epigenetic regulator of glycolysis-related metabolic enzymes in HCC and identifies the p300/CBP inhibitor B029-2 as a potential therapeutic strategy in this disease.

Synthesis of 5α-cholestan-6-one derivatives and their inhibitory activities of NO production in activated microglia: discovery of a novel neuroinflammation inhibitor.

Glial activation-mediated neuroinflammation plays a pivotal role in the process of several neuroinflammatory diseases including stroke, Alzheimer's diseases, Parkinson's diseases, multiple sclerosis and ischemia. Inhibition of microglial activation may ameliorate neuronal degeneration under the inflammatory conditions. In the present study, a number of 5α-cholestan-6-one derivatives were prepared and the anti-inflammatory effects of these compounds were evaluated in LPS-stimulated BV-2 microglia cells. Those derivatives were synthesized from readily available hyodeoxycholic acid (1). Among the tested compounds, several analogs (16-18, 25, 35, 38) exhibited potent inhibitory activities on nitric oxide production with no or weak cell toxicity. Compound 16 also significantly suppressed the expression of TNF-α, interleukin (IL)-1ß, cyclooxygenase (COX-2) as well as inducible nitric oxide synthase (iNOS) in LPS-stimulated BV-2 microglia cells. In addition, compound 16 markedly reduced infarction volume in a focal ischemic mice model.

Bis-triazolyl indoleamines as unique "off-approach-on" chemosensors for copper and fluorine.

Bis-triazolyl indoleamine-based chemosensors that respond to copper, and then fluorine as presumably facilitated by the high-affinity interaction between F(-) and the NH-proton of indole, are reported. Remarkable fluorimetric as well as colorimetric alternations upon the specific ligand-ion recognitions were observed.

Synthesis and hepatitis†C antiviral activity of 1-aminobenzyl-1H-indazole-3-carboxamide analogues.

FIGHTING HCV: Two potent antiviral analogues were developed from a previously identified lead as novel agents against hepatitis C virus. Their potency and selectivity (5 n: IC50 =0.013 µM and EC50 =0.018 µM; 5 t: IC50 =0.007 µM and EC50 =0.024 µM) make them good candidates for further development as antiviral agents.

Triptolide: structural modifications, structure-activity relationships, bioactivities, clinical development and mechanisms.

Triptolide, a principal bioactive ingredient of Tripterygium wilfordii Hook F, has attracted extensive exploration due to its unique structure of a diterpenoid triepoxide and multiple biological activities. This review will focus on the structural modifications, structure-activity relationships, pharmacology, and clinical development of triptolide in the last forty years.

[Polymorphism of the 5R-5-hydroxytriptolide].

5R-5-hydroxytriptolide (LLDT-8) is a new drug candidate which is in clinical trial treating rheumatoid arthritis. Polymorph screening of the compound was carried out in this study. Polymorph of LLDT-8 was prepared by evaporative crystallization and antisolvent crystallization methods and was characterized by powder X-ray diffraction (p-XRD), infrared spectrometry (IR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TG). It was found that p-XRD patterns, DSC curves, TG curves and IR spectra of the LLDT-8 samples prepared by the above recrystallization methods were all consistent. The 20 of main peaks in the p-XRD patterns appeared at 7.58 degrees, 8.14 degrees, 8.66 degrees, 15.46 degrees, 16.46 degrees, 29.54 degrees, 31.16 degrees and 38.26 degrees, while the infrared absorption peaks appeared at 3 471.3, 2 962.2, 2 887.0, 1 762.6, 1 677.8, 1 432.9, 1 365.4, 1 247.7, 1 080.0, 1 031.7 and 877.5 cm(-1). LLDT-8 was decomposed at 271.2 degrees C based on the determination from DSC and TG. It was showed in single crystal X-ray diffraction study that LLDT-8 crystal was monoclinic with the space group being P2 (1). The cell parameters were found to be: a = 11.460 1 (11), b = 6.320 5 (6), c = 13.028 1 (12), alpha = 90.00, beta = 115.557 (2) and gamma = 90.00. The crystal was a hydrogen-bonded dimmer. The slurry experiments, which were further conducted in solvents with different polarities, confirmed the stability of solid state of LLDT-8 based on the p-XRD determination. The polymorph of LLDT-8 made assurance of its efficacy consistence during its clinical trials.